Automatic damper control



Dec. 10, 1940. s. E STRINGER AUTOMATIC DAMPER CONTROL Filed 001:. 29, 1938 59 E ifi ijfi" M HIS ATTORNEY.

Patented Dec. 10, 1940 UNITED STATES PATENT OFFICE 8 Claims.

This invention pertains to control mechanism for use with heating and combustion systems employing a damper or analogous device, a principal object being the provision of mechanism coacting with a damper and an electrically operated or controlled fuel supplying means for openin the damper more or less completely at the instant the heating or combustion device is set into operation and thereafter closing the m damper more or less completely when combustion has been in progress a predetermined length of time.

Viewed from another aspect, it is an important object of the invention to provide control mechanism for use with oil burners, stokers, and analogous combustion devices in which the fuel supplying means is electrically operated or controlled and in which there is an ignition device for lgniting the fuel when the fuel supply means is energized, the control mechanism including electrical means arranged in circuit with the fuel supplying and ignition means so that when the fuel supplying and ignition means are energized the damper will be opened more .or less completely,

there being mechanism arranged to cut out the ignition means as soon as combustion is in progress, and the control mechanism coacting with the ignition cut-out means to permit and eflect closing of the damper to greater or less degree,

the control mechanism further coacting with the fuel supply means so that the damper will be entirely closed when the fuel supply means is out 01f or deenergized.

In still another of its aspects, the invention provides automatic control means for use with oil burners, stokers, and analogous combustion devices for increasing the efiiciency of such devices, for obviating dangers due to inital combustion flashes, and for preventing the formation of obnoxious gases, fumes, and the like, due to initial combustion reaction in those arrangements where the damper is normally closed to greater or less degree, the control mechanism being arranged to effect opening of the damper to permit easy egress of the combustion gases when the combustion device is set into operation, as by pumping and igniting an oil spray, or when fuel is additionally fed into the fire, as in the case of an automatic stoking device.

A specific object of the invention is the provision of control means including a plurality of electromagnets arranged for joint and several operation to open and close a damper various amounts, the electromagnets being arranged in circuit with fuel supply and igniting means so that the damper will be entirely opened at the time of ignition and subsequently closed a certain amount either due to a lapse of time or due to the establishment of a predetermined temperature in the flues or other part of the system. 5

Other objects, advantages, and economies residing in the invention pertain to certain details of construction and operation of the parts of the illustrative embodiment described hereinafter in conjunction with the annexed drawing, in which:

Fig. 1 is a front elevation of the control oper ating mechanism;

Fig. 2 is a vertical side section along line 2-2 of Fig. 1, including the damper;

Fig. 3 is a circuit diagram; and

Fig. 4 is a. modified circuit diagram.

The control mechanism of my invention is intended for use with combustion devices, such as oil burners and stokers, which employ a breeching or flue Ill (Fi s. 1 and 2) communicating with 20 the combustion chamber from a stack, and which are provided with a damper ll pivotally mounted as at l2 to swing into opening and closing position across the flue I0, the damper being shown in closed position in Fig. 2. 25

The damper ll swings about a horizontal axis on a spindle l3 secured thereto by the screw means I4 in a struck-up sleeve portion 15 according to the usual damper construction, the spindle extending through a sleeve l-B which terminates 30 in a bushing I! on the back wall H! of a housing 20, an end of the spindle being secured in the hub 2| of a lever arm 22. Rocking of the arm 22 effects movement of the damper into various open and closed positions, and this arm is pro- 35 vided. with an extension 23 on which is a counterweight 24 normally lowered against a stop 25 to turn the damper into completely closed position. Means for moving and maintaining the damper H in various open positions, includes the pro- 40 vision of lever mechanism including members which are jointly or severally operable to efiect movement of the damper different amounts toward openposition. In one of its forms, this mechanism includes a link 30 pivoted as at 3| to 45.

40 and 4| may be moved downwardly together with a resultant downward pull on the damper operating arm 22, due to the connection of the driving members through the differential arm 33 and the link 30 with the damper arm 22.

It will also be observed that either of the driving members 40 or 4| may be pulled down alone with a resultant downward pull on the link 30 and hence on the damper operating arm 22; however, in the latter case, due to the differential connection 33 with the link 30 the damper arm 22 will be moved a lesser distance when only one of the actuating or driving members 40 or 4| is pulled down than would be the case if both of the latter members operated together. Thus, the several movements of the differentially connected driving or actuating components of the lever mechanism will open the damper a. predetermined amount, whereas the joint operation of the components of the differential means will move the damper a greater amount.

The means for actuating the differential mechanism is preferably electrically energized and includes a pair of solenoids 42 and 43 each mounted on the wall panel l8 beneath one of the members 40 or 4|, the latter being magnetically attractable and constituting cores or armatures for the solenoids, and being drawn downwardly when either of the solenoids is energized.

In one circuit arrangement, illustrated in Fig. 3, suitable for use with stokers or certain types of burners omitting ignition means, one terminal of the solenoid winding 43 is connected by a conductor 45 to one terminal of a heating element 46, the remaining terminal of the latter being connected by conductor 41 to one contact 53 of a. thermostatic master control switch, the remaining contact 54 of which switch is connected to one terminal 48 of the power line, while the remaining terminal of the solenoid winding 43 is connected by conductor 50 to one terminal of the electrically energized fuel supply means 5|, in this case a motor, the remaining terminal of the latter being connected by conductor 52 to the return side or terminal 4a of the power line. Thus, the damper actuating solenoid 43 is connected in series with the heating element 46 and the fuel supplying means or motor 4| so that when the thermostatic switch 53 is closed, the solenoid 43 will be energized. The thermostat 53 is arranged in an apartment which is heated by the combustion device and when the temperature varies from a predetermined figure, the

fuel supply means or motor is automatically started.

In the arrangement of Fig. 3, the ignition means may or may not be employed, depending upon the nature of the combustion system,

whether it is of the intermittently operable or continuously operable type.

In the case, for example, of an oil burner, one terminal of an ignition coil 55 is connected by a conductor 56 to one contact 51 of a shunting switch and also to the terminal 49 of the powerline (in common with the conductor 52 on the motor), the opposite terminal of the ignition coil being connected to the remaining terminal 58 of the shunting switch and also via conductor 59 to one of the terminals 60 of a thermostatic time-delay switch actuated by the heating element 46, the remaining terminal 6| of the time delay switch being connected by conductor 62 to one terminal of the solenoid winding 42, and the remaining terminal of the latter being connected by conductor 63 to the contact 53 0f the master thermostatic switch and through the latter to the remaining terminal 48 of the powerline. Thus, the solenoid 42 is connected in series with the switch means 4660-6|, and also with the ignition coil 55, depending upon whether the shunt switch 51 is open or closed.

Assuming the arrangement of Fig. 3 to be used in conjunction with an oiliburner employing an ignition coil 55, the shunt switch 51 may be opened, and as soon as the master thermostatic switch closes, current will flow in one side cir- .cuit through the solenoid winding 43, the timedelay heater element 45, and the motor 5|, and at the same time through another side or branch circuit including the ignition coil 55, the contacts of the time-delay switch Gil-6| and the winding of the solenoid 42. Operation of the master thermostatic switch 53 will therefore effect simultaneous energization of both of the solenoids 42 and 43 and also of the ignition coil and the motor, and as a result of the energization of the solenoids both of the members 40 and 4| (Fig. 1) will be pulled down to the limit of their movement, with a consequent pivoting of the damper operating members 222324 into the uppermost dotted line position corresponding to fully open position of the damper.

Upon closing of the master thermostatic switch 53, the electrically energized operating or control means, that is, the motor 5|, for the fuel supplying mechanism (1. e. a pump, blower, injection means, stoker or the like), will feed fuel into the combustion chamber for ignition by the operation of the coil 55, and the gases and pressure in the combustion chamber, resulting from the initial reaction of ignition, will be provided with a means of egress through the flues in the usual manner due to the fact that the damper II has been opened by joint operation of the solenoids 42 and 43. After combustion has been in progress for a relatively short interval, the timedelay or thermostatic switch means 46-606| will open and deenergize the solenoid 42, with the result that the plunger 40 and the corresponding side of the differential lever 33 will move upwardly, this movement being limited by a stop 44 (Fig. 1) so that the damper lever means 222324 will be permitted to drop back to the intermediate dotted line position shown in Fig. 1, with a resultant partial closing of the damper so that less of the heat will be permitted to pass up the flues. When the normal predetermined temperature has been restored in the heated compartment, the thermostatic switch 53 will open, stopping the fuel supplying means and deenergizing the solenoid 43 with a consequent upward movement of the plunger 4| of the latter and a consequent restoration of the damper lever means 222324 to its initial (full line) position.

In the event that the combustion system is of the continuous operation type, for example, a stoker-fired furnace, the ignition means 55 will not be needed and is shunted out of the circuit by closing the switch 51. In other respects, the circuit arrangement of Fig. 3 will then operate in the same manner as when used with an oil burner. The time-delay switch means 46-606| is preferably mounted on the panel 18 along with the solenoids, and may be of the adjustable type, if desired.

Another circuit arrangement which is particularly suited for use with oil burners is shown in Fig. 4, wherein one terminal of the solenoid winding 42 is connected by a conductor 10 to one terminal ll of a thermostatic switch whose remaining terminal 12 is connected by conductor I3 to a terminal of an ignition coil 14, and the remaining ignition coil terminal is connected to a contact 15 of a master thermostatic switch having a contact I6 connected to one terminal ll of the power line, "the opposite terminal 18 of which is connected by a conductor 19 to the remaining terminal of the solenoid winding 42. Thus, one of the damper, operating solenoids is connected in series with a thermostatic stack switch, the ignition coil, and the master thermostatic switch.

One terminal of the other solenoid winding 43 is connected by a conductor 80 to the master thermostatic switch contact 15 and through the latter to one side of the line, the remaining terminal of the winding 43 being connected by a conductor 8| through the fuel supply means or motor 82 and a conductor 83 to the return side 18 of the power line. When the master switch 15-46 is closed, both the ignition coil and the fuel supply means or motor are energized simultaneously with the two solenoids 42 and 43. The thermostatic stack switch ll-12 is normally closed and is preferably situated in the flue or stack in a position to be heated by the hot gases issuing from the combustion chamber. When the two solenoids pull up, the damper is opened and an exhaust opening through the fines provided for the increase in pressure and the gaseous products of combustion resulting from the initial combustion reaction. The stock switch ll-l2 is preferably arranged to open as a result of heating by the exhaust gases a short time after combustion is started, the period of time being in all cases adequate to permit the proper conditions of pressure to be established in the combustion line and to assure that all obnoxious gases, smoke, and the like, will have been carried up the flue.

When the switch II-l2 opens, the solenoid 42 will be denergized and the damper operating lever 22 will be permitted to assume the intermediate position heretofore described and corresponding to partly open position of the damper. At the same time the ignition coil 14 will be cut out of the circuit. Opening of the master switch IS-J6 will denergize the motor and the remaining solenoid, and the damper will be restored to fully closed position.

Other forms of time-delay or supervisory switching means may be used in place of the heater-operated switch means 46-60-45! of Fig. 3 or the ordinary thermostatic switch ll-I2 of Fig. 4, and, if desired, the circuits respectively controlled by the aforesaid switching means may be placed directly under manual control in installations where such an arrangement is desirable. Moreover, the circuit of Fig. 4 may be used in conjunction with heating plants which do not employ an ignition means but are in constant operation, the stack control switch or equivalent means being arranged for operation by a rise in temperature in any convenient part of the combustion line.

The objects and advantages of the invention may be realized by other forms of construction and modes of operation of the arrangements described in detail for purposes of illustration, and it is a condition of this disclosure that the appended claims are to include all equivalent means and arrangements.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. Control mechanism for use with dampers and analogous devices, said mechanism including in combination, an operating member adapted for operative connection with a damper or the like, a pair of solenoids each having a plunger movable substantially collaterally with respect to the plunger of the other, and linkage means operatively interconnecting said plungers and said operating member for movement of the latter diiierent amounts from a normal position when said plungers are attracted by their respective solenoids, the amount of movement of said operating member depending upon the number of said solenoids operated .at a given time, means yieldingly urging said operating member into said normal position, and means for selectively energizing said solenoids to actuate the same simultaneously or separately.

2. In combination, a damper arranged for pivotal movement from normally closed to open position, ever means for pivoting said damper, means operatively associated with said lever means for yieldingly urging said damper toward closed position, a pair of magnetically attractable members arranged for back and forth movement side by side in the same direction, link means connected with each of said magnetically attractable members, a diiferential lever arm pivotally interconnecting the aforesaid link means, means pivotally connected with said lever means and with said difi'erential arm at a point on the latter between the pivotal connections thereof with said link means whereby said lever means may be pivoted by joint or independent movement of said magnetically attractable members, the distance which said lever means is pivoted depending upon whether one or both of linking said lever with said armatures for movement of the lever by one or more of said armatures when the latter are attracted by their respective solenoids, said means comprising a differential lever arm pivotally connected between its ends to said damper operating lever, a plurality of link means having pivotal connection with said diiferential arm at points on opposite sides of the connection of said arm with said operating lever, each of said link means in turn having pivotal connection with one of said armatures, means coacting with the damper and said operating lever for moving the latter and said armatures into a normal position, the degree of movement of said operating lever from normal position depending upon the number of' solenoids operated at a given time, and means for energizing said solenoids separately or together.

4. In a control mechanism for a damper, a pair of collaterally reciprocable operating members, a differential lever pivotally linked with each of said members, a damper operating lever having pivotal connection with said differential lever at a point between the linkage of the latter with 5. The combination, with a damper, oi oper-' ating means for moving .the same difierent amounts, said operating means comprising a pair of solenoids and means for energizing the same jointly or severally, each solenoid having a plunger attractable thereby, link members each pivotally attached to an end of one of said plungers, a differential lever arm having opposite end portions each of which is pivotally connected with one of said link members, and a damper operating lever having pivotal connection with said differential arm at a point between the ends of the latter and having pivotal connection with said damper.

6. A control device including a main operating lever and a differential lever pivotally attached between its ends to said main operating lever for pivotal movement in opposite: directions, electrically actuated devices each having operative connection with one of said opposite ends of the differential lever for operation severally to pivot said lever in opposite directions and thereby move said main operating lever a certain distance, said electrically actuated devices being operable jointly to move said main operating lever a greater distance resulting from the bodily displacement of said differential lever by joint action of said electrically actuated devices.

7. In a damper control, a pivotable lever arranged to move a damper, and means yieldably urging said damper lever into a normal position, an operating lever having pivotal connection at one end with said damper lever, an opposite end portion of said operating lever being pivotally connected between the ends of a differential lever arm, a pair of solenoids each having a plunger arranged for collateral reciprocation in the general direction of movement of said operating lever into and out of normal position, and a link pivotally connecting the end of each plunger with an end of said differential arm, said solenoids being connected in a control circuit for energizing the same jointly or severally, said piungers being withdrawn from attracted position by action of said yieldable urging means.

8. In a damper control, a damper'operating member and means for displacing said member different amounts from a normal position and comprising a plurality of electromagnets each having an armature member operatively associated with said operating member for joint or several coaction therewith and arranged and constructed to displace the same different amounts dependent upon the number of said electromagnets operated at a given time, minimum displacement being effected by the least number of electromagnets operated as aforesaid, and maximum displacement being effected by the greatest number of electromagnets operated at a given time as aforesaid, and means yieldingly urging said operating member into said normal position.

GEORGE E. STRINGER. 

